Development of a submersible centrifuge to replace the metal screens used for collection of uranium metal product;
Demonstration of oxide reduction processes in the FCF; and
Development of procedures for treating rubble from the Three Mile Island reactor, U-Zr hydride fuels, and spent or damaged fuels from the Power Burst Facility (PBF) and Loss of Fluid Test Reactor (LOFT).
Electrorefining has been carried out by ANL on an engineering scale (10 kg of heavy metal/day) with unirradiated metal fuel. For the upcoming EBR-II demonstration, this equipment will be used in the FCF to process about 1 metric ton of EBR-II driver fuel. A high-throughput electrorefiner (200 kg heavy metal/day), currently being developed at ANL-East, will be used to process about 16 metric tons of EBR-II blanket fuel in the FCF. The EBR-II campaign should demonstrate the applicability or nonapplicability of the electrometallurgical process to the production-scale treatment of irradiated metallic fuels.
Laboratory experiments at ANL-East have shown that a TRU-depleted zeolite waste form could be produced from the electrorefiner's salt effluent and that the purified salt could be returned to the electrorefiner for reuse. However, this waste form is at a very early stage of development.
Treatment of the metal waste stream that consists of cladding and noble metal fission products is still under study. This proposed waste form would be prepared by combining the anode waste stream with stainless steel filter cartridges from the bulk fluid handling system. This mixture would be melted with a small amount of zirconium to produce a relatively lower melting eutectic.
The uranium from the electrorefiner's steel cathode requires processing to remove entrained salt and produce a uranium ingot. This is a major process step that would take place in an inert atmosphere in the cathode processor. The process has been tested with unirradiated uranium cathode deposits only, and it must be demonstrated at a production scale under inert-atmosphere conditions with actual spent fuel.
ANL's program for federal FY1995 through FY1997 calls for intensive R &D efforts to develop effluent processing procedures on an engineering scale and to demonstrate the processes in the FCF for EBR-II fuel.